Manufacture of ferrophosphorus



Patented Oct. 18, 1927. I l

UNITED STATES PATENT OFFICE.

JOSEPH WARNER, F NASHVILLE, TENNESSEE.

MANUFACTURE OF FERROPHOSPHORUS.

R0 Drawing. Application filed June 16, 1927. Serial No. 199,406.

My invention relates to the production of phorus. It is doubtful if a higher percentferro-phosphorus and has particularly in age could be obtained with the limited i a t t process f akin the amount of silicious matter used. This is all I the first step in my process. v

6 In prior processes for making ferro-phos- In order to increase the phosphorus conphorus, large quantities of silicious matter tent of the alloy, I first make and lay aside, are dd d t th charge so that a, lar e say 1000 tons of the loW-fgrade ferro phosamount of phosphate rock or bone phosphate phorps produced in the rst step. I then so of lime may be added with 'which to neuput it through the furnace a second time,

10 tralize the silicious matter in order to have charging the furnace substantially as bea sufficient amount of phosphorus present to fo e, but using as the metallic part of the enter the reduced metal and make a standg ne 0f the 10W grade ferro phos ard grade of ferro-phosphorus containing ph rusfor instance to the remainas f i t 18% f ho h I th d er of the metallic charge being substan- 16 usual blast furnace practice, the silicious y 3S 1 he fi st charge. The propormatter comes largely from the added iron 110118 of metalllc Substance w -P Th r are di d t i ddi phorus to be used can be readily determined large quantities of'silicious matter because yactual practlce, s y qm 1 to 100%. 70 the most expensive part of blast furnace opyp al dl ge not using iron ore and 20 erations is the fluxing of the silicious matter a g y l c ous phosphate rock, which can f hi h thi f value can b h d d be used as in the first step of the process is the large amount of slag produced is expenas follows! sive to dispose of. A large amount of slag (I 1 also carries off a large amount of phosphorus Chma- 35 that cannot be recovered. R

My process therefore is directed to the amalgam 7 g a production of ferro-phosphorus in which a 5T0! phosphate rock 17 850 minimum amount of slag will be produced, 250olbs: metallic lron :::I 6 125 With this idea in view therefore, I subs i- E0 i TE 30 tute for the large quantities of high silicious bearing iron ores of prior processes, metallic 50001b 50% h h t o k=B P, L, iron, such as scrap, or a mixture of metal 27% fl i bflit =1350 and iron ore; or I may use iron ore with a A id t li 07 smaller amount of silicious matter alone, in- 85 stead of the large quantities of high silicious Farm phosphmm ores now used. In any combination of ma- 5000 lbs. 50% phos hate rock B. P. L, terials which may form the charge it is 9% avai able phosphorus 450 essential that the total amount of silica shall 2500 lbs. metallic iron 2250 90 be much less than in prior processes in order 40 It)ha't ogly a1 minimum amount'of slag shall 2700 e ro uce fly p fi fi is i follows: gle tifii 1s 15% plus of phosphorus in the The co *e, p osp ate rock and the iron bearin material are charged into the top The second Step Is as follows 45 of the ilast furnace and in such proportions Char that only enough phosphate rock or bone m Pmmds' phosphate of-lime is added to combine with the limited amount of silicious and other acid matters in the coke, the phosphate rockii iigiiigb'liififii 17 i3 3 and the iron bearing material. In this man- 3530313 $3 3? g 75 ner, I produce form-phosphorus containing on the average from 10 to 16% of phos- 1393 Phosphate rock. 5000 lbs. 50% B. P.L..=

27% Fluxing ability, 1350. Acids to lime, 1.03.

Ferro phosphorus.

5000 lbs. 50% phosphate rock.

9% available phosphorus- 450 1250 ferro phosphorus 15% P 187 1250 Ierro phosphorus 85% I 1063 1250 metallic iron 90% 1125 which is 22% plus of phosphorus in the metal. If it is desired to add mill cinder and a high grade hosphate r0 as a part of the charge the ollowing proport1ons have been found practicable:

Acids which is 13% plus of phosphorus in themetal.

The second step would be as 01105; using a greater amount of ferro phosphorus V 3000 lbs. phosphate rock B. P. L. r 40% fiuxing ability, 1200.

Acids to lime, 1.06.

Ferro phosphorus.

3000lbs. 7 5% phosphate rock.

15% available phosphorus-" 450 1800 lbs. ferro phosphorus, 13% phosphorus 1800 lbs. ferro phosphorus, 87% iron 1560 600 lbs. scrap, 90% 540 18001bs. mill cinder, 50%. 900

3690 which is 18% plus of phosphorus in the metal.

If it is desired to use only iron ore, then the following charge can be used:

Lime. Charge. Acids.

Pa cent. 3600 lbs. ooke..- 13 40s 75% phosphate rock has 2700 lbs. phosphate 5 125 40% Busing abilityrock. 1080 lbs. 4600 lbs. iron ore 15 600 $00 103 Lime, 1080. Acids, 1218'1.10 acids to lime.

v Phosphoruslbs. 2700 lbs. 75%- rock15% available ph0sphorus Q05 4500 lbs. iron ore, 48% yield 2160 Ferro phosphorus 2565 which is 15% plus of. phosphorus in themetal.

The second step is about as follows supplying necessary silicious matter from mill cinder and ore:

2700 lbs phosphate rock 75 B. P. 40% fluxing ability, 1080. Acids to lime, 1:10 I Ferro phosphorous.-

' first put into the metal and that this alloy so produced is remelted for the purpose of increasing the phosphorus to the required market percentage. My'process involving which is 20% plus of phosphorus in the Pounds.

2700 lbs. phosphate rock 15% available 450 Char 1500 form phosphorus,- 15% phosphorus 225 5,1 1500 -ferr0 phosphorus, 85% iron 1275 g-"1" L wk {g 1500 mill cinder, 50% 750 lstlllbsil erro phosphorusa 1500 ore, 45% 675' -61 lbs. scrap -L 5 3) 1800lbs. millcinder 35 630 1m 3375 two steps to attain the desired percentage V of phosphorus in the alloy is found to be cheaper and better than the one step process in which a large quantity of silicious matev rial is necessary.

Owing to the use in my new process of a larger quantity of metallic iron in some form, a less quantity of hot air will be necessary in carrying out the process and will be desirable from an economic standpoint. This decrease in air will also prevent excessive volatilization of phosphorus passing off in the escaping gases, as is the case in the usual ferro phosphorus furnace practice of using large quantities of air which is necessary for the reduction, proper working, and fluxing of a high silicious burden or charge.

The affinity of phosphorus for iron strong. They will readily unite when brought together in the molten state but it requires a very hi 11 degree of heat to unite them to the best a vantage. By my process, on account of the small amount of silicious matter, the furnace can be operated at a much higher degree of heat than in the old practice. Metallic iron melts higher up in the blast furnace than iron ores and for this reason the molten metal is exposed to the action of the phosphoric gases longer and at a greater heat and will thus absorb more phosphorus than in the usual practice. By my process, it is possible to recover 90% up of all phosphorus put into the top of the furnace. The loss of phosphorus in the usual practice is to 40%.

While I have described my process in connection with the production of ferrophosphorus in a blast furnace, with suitable modification, the same principles are applicable in electric furnaces.

\Vhat I claim as new and desire to secure by Letters Patent is:

1. The process of producing a high percentage ferro-phosphorus which comprises charging the furnace with a mixture containing ferro-phosphorus, coke and phosphate bearing material and a metallic substance, the amount of phosphate bearing mais very terial being added in only such quantity as to provide the necessary fluxing ability to combine with the silica in the said mixture.

2. A two step process for producing ferro phosphorus which comprises charging the furnace with a mixture containing iron bearing material, coke and phosphate bearing material, the amount of ing material being added in only such quantity as to provide the necessary fluxmg ability to combine with the silica in the said mixture, then taking the ferro phosphorus so produced and adding it as a part of a similar charge, wherebv its percentage of phosphorus is increased.

3. A two step process for producing ferro phosphorus which comprises charging the furnace with a mixture containing iron bearing material, coke and phosphate bearing material and smelting the same to produce a ferro-phosphorus containing substantially 10*1670 of phosphorus and thereafter increasing the percentage of phosphorus by adding the ferro phosphorus alloy as a part of another charge.

4. A two step process for producing ferro phosphorus which comprises charging the furnace with suitable iron-bearing material, coke and phosphate bearing material, the total amount of silica in the charge being so limited as to produce a ferro phosphorus havin only a relatively small amount of phosp iorus and thereafter increasing the percentage of phosphorus by adding the ferro-phosphorus alloy as a part of another charge.

In testimony whereof, I hereby aflix my signature.

JOSEPH WARNER.

phosphate bear- 

